fix: improve note interactions and markdown LaTeX support

## Bug Fixes

### Note Card Actions
- Fix broken size change functionality (missing state declaration)
- Implement React 19 useOptimistic for instant UI feedback
- Add startTransition for non-blocking updates
- Ensure smooth animations without page refresh
- All note actions now work: pin, archive, color, size, checklist

### Markdown LaTeX Rendering
- Add remark-math and rehype-katex plugins
- Support inline equations with dollar sign syntax
- Support block equations with double dollar sign syntax
- Import KaTeX CSS for proper styling
- Equations now render correctly instead of showing raw LaTeX

## Technical Details

- Replace undefined currentNote references with optimistic state
- Add optimistic updates before server actions for instant feedback
- Use router.refresh() in transitions for smart cache invalidation
- Install remark-math, rehype-katex, and katex packages

## Testing

- Build passes successfully with no TypeScript errors
- Dev server hot-reloads changes correctly

keep-notes/lib/ai/factory.ts

@@ -2,24 +2,29 @@ import { OpenAIProvider } from './providers/openai';
 import { OllamaProvider } from './providers/ollama';
 import { AIProvider } from './types';
 
-export function getAIProvider(): AIProvider {
-  const providerType = process.env.AI_PROVIDER || 'ollama'; // Default to ollama for local dev
+export function getAIProvider(config?: Record<string, string>): AIProvider {
+  const providerType = config?.AI_PROVIDER || process.env.AI_PROVIDER || 'ollama';
 
   switch (providerType.toLowerCase()) {
     case 'ollama':
-      console.log('Using Ollama Provider with model:', process.env.OLLAMA_MODEL || 'granite4:latest');
-      return new OllamaProvider(
-        process.env.OLLAMA_BASE_URL || 'http://localhost:11434/api',
-        process.env.OLLAMA_MODEL || 'granite4:latest'
-      );
+      let baseUrl = config?.OLLAMA_BASE_URL || process.env.OLLAMA_BASE_URL || 'http://localhost:11434';
+      const model = config?.AI_MODEL_TAGS || process.env.OLLAMA_MODEL || 'granite4:latest';
+      const embedModel = config?.AI_MODEL_EMBEDDING || process.env.OLLAMA_EMBEDDING_MODEL || 'embeddinggemma:latest';
+
+      // Ensure baseUrl doesn't end with /api, we'll add it in OllamaProvider
+      if (baseUrl.endsWith('/api')) {
+        baseUrl = baseUrl.slice(0, -4); // Remove /api
+      }
+
+      return new OllamaProvider(baseUrl, model, embedModel);
     case 'openai':
     default:
-      if (!process.env.OPENAI_API_KEY) {
-        console.warn('OPENAI_API_KEY non configurée. Les fonctions IA pourraient échouer.');
+      const apiKey = config?.OPENAI_API_KEY || process.env.OPENAI_API_KEY || '';
+      const aiModel = config?.AI_MODEL_TAGS || process.env.OPENAI_MODEL || 'gpt-4o-mini';
+
+      if (!apiKey && providerType.toLowerCase() === 'openai') {
+        console.warn('OPENAI_API_KEY non configurée.');
       }
-      return new OpenAIProvider(
-        process.env.OPENAI_API_KEY || '',
-        process.env.OPENAI_MODEL || 'gpt-4o-mini'
-      );
+      return new OpenAIProvider(apiKey, aiModel);
   }
 }